1. Field of Invention
The present invention relates to a prediction circuit of a video system, and more particularly to an intra prediction circuit device applied to the H.264 video coding standard.
2. Description of Related Art
Recent development of MPEG2, MP3, VCD and DVD multimedia products have made H.264 and MPEG4 video coding functions with higher video quality compression rates, lower bit rates and simplified programs be a basic requirement for multimedia products. Moreover, H.264 and MPEG4 video coding functions further include higher integrated communication capability. As a result, the H.264 and MPEG4 video coding functions are generally applied to digital video products.
The H.264 and MPEG4 technologies are broadly implemented on digital video equipments with high-density stored image requirement such as digital monitor systems, digital cameras, digital DV recorders, portable MPEG4 (DivX) multimedia players, portable mobile digital video recorders (DVR), digital video broadcasting (DVB), set-top-boxes (STB) and so on. Furthermore, the MPEG4 PVR with video on Demand (VOD) has been applied to the IP STB (Internet) to enhance the resolution of the digital television.
H.264/AVC (Advanced Video Coding) is the video compression standard established by the Video Coding Experts Group (VCEG) of ITU-T and the Moving Picture Experts Group (MPEG) of International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC). Compared with the previous video standard MPEG, H.264 provides a compression quality with approximately double the compression rate.
The H.264/AVC video standard consists of many modes, wherein the intra prediction mode plays an important role to enhance the compression rate of the still images. There are nine kinds of formats with 4×4 blocks and four kinds of formats with 16×16 macroblocks in the intra prediction mode of the H.264 where these thirteen prediction modes are applied to video coding to enhance the compression rate of the images. Compared with the compression quality of the still images in accordance with the prior art, the peak signal to noise ratio (PSNR) value is about 0.1-0.8 db higher than the JEPG-2000 DWT53. In order to achieve the higher resolution, immediate intra prediction and immediate coding, decreasing the computation to enhance efficiency and output rate is a critical issue.